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dir-item.c

/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include "ctree.h"
#include "disk-io.h"
#include "hash.h"
#include "transaction.h"

static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
                                       *trans,
                                       struct btrfs_root *root,
                                       struct btrfs_path *path,
                                       struct btrfs_key *cpu_key,
                                       u32 data_size,
                                       const char *name,
                                       int name_len)
{
      int ret;
      char *ptr;
      struct btrfs_item *item;
      struct extent_buffer *leaf;

      ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
      if (ret == -EEXIST) {
            struct btrfs_dir_item *di;
            di = btrfs_match_dir_item_name(root, path, name, name_len);
            if (di)
                  return ERR_PTR(-EEXIST);
            ret = btrfs_extend_item(trans, root, path, data_size);
            WARN_ON(ret > 0);
      }
      if (ret < 0)
            return ERR_PTR(ret);
      WARN_ON(ret > 0);
      leaf = path->nodes[0];
      item = btrfs_item_nr(leaf, path->slots[0]);
      ptr = btrfs_item_ptr(leaf, path->slots[0], char);
      BUG_ON(data_size > btrfs_item_size(leaf, item));
      ptr += btrfs_item_size(leaf, item) - data_size;
      return (struct btrfs_dir_item *)ptr;
}

int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root, const char *name,
                      u16 name_len, const void *data, u16 data_len,
                      u64 dir)
{
      int ret = 0;
      struct btrfs_path *path;
      struct btrfs_dir_item *dir_item;
      unsigned long name_ptr, data_ptr;
      struct btrfs_key key, location;
      struct btrfs_disk_key disk_key;
      struct extent_buffer *leaf;
      u32 data_size;

      key.objectid = dir;
      btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
      key.offset = btrfs_name_hash(name, name_len);
      path = btrfs_alloc_path();
      if (!path)
            return -ENOMEM;

      data_size = sizeof(*dir_item) + name_len + data_len;
      dir_item = insert_with_overflow(trans, root, path, &key, data_size,
                              name, name_len);
      /*
       * FIXME: at some point we should handle xattr's that are larger than
       * what we can fit in our leaf.  We set location to NULL b/c we arent
       * pointing at anything else, that will change if we store the xattr
       * data in a separate inode.
       */
      BUG_ON(IS_ERR(dir_item));
      memset(&location, 0, sizeof(location));

      leaf = path->nodes[0];
      btrfs_cpu_key_to_disk(&disk_key, &location);
      btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
      btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
      btrfs_set_dir_name_len(leaf, dir_item, name_len);
      btrfs_set_dir_data_len(leaf, dir_item, data_len);
      name_ptr = (unsigned long)(dir_item + 1);
      data_ptr = (unsigned long)((char *)name_ptr + name_len);

      write_extent_buffer(leaf, name, name_ptr, name_len);
      write_extent_buffer(leaf, data, data_ptr, data_len);
      btrfs_mark_buffer_dirty(path->nodes[0]);

      btrfs_free_path(path);
      return ret;
}

int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
                    *root, const char *name, int name_len, u64 dir,
                    struct btrfs_key *location, u8 type, u64 index)
{
      int ret = 0;
      int ret2 = 0;
      struct btrfs_path *path;
      struct btrfs_dir_item *dir_item;
      struct extent_buffer *leaf;
      unsigned long name_ptr;
      struct btrfs_key key;
      struct btrfs_disk_key disk_key;
      u32 data_size;

      key.objectid = dir;
      btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
      key.offset = btrfs_name_hash(name, name_len);
      path = btrfs_alloc_path();
      data_size = sizeof(*dir_item) + name_len;
      dir_item = insert_with_overflow(trans, root, path, &key, data_size,
                              name, name_len);
      if (IS_ERR(dir_item)) {
            ret = PTR_ERR(dir_item);
            goto out;
      }

      leaf = path->nodes[0];
      btrfs_cpu_key_to_disk(&disk_key, location);
      btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
      btrfs_set_dir_type(leaf, dir_item, type);
      btrfs_set_dir_data_len(leaf, dir_item, 0);
      btrfs_set_dir_name_len(leaf, dir_item, name_len);
      name_ptr = (unsigned long)(dir_item + 1);

      write_extent_buffer(leaf, name, name_ptr, name_len);
      btrfs_mark_buffer_dirty(leaf);

      /* FIXME, use some real flag for selecting the extra index */
      if (root == root->fs_info->tree_root) {
            ret = 0;
            goto out;
      }
      btrfs_release_path(root, path);

      btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
      key.offset = index;
      dir_item = insert_with_overflow(trans, root, path, &key, data_size,
                              name, name_len);
      if (IS_ERR(dir_item)) {
            ret2 = PTR_ERR(dir_item);
            goto out;
      }
      leaf = path->nodes[0];
      btrfs_cpu_key_to_disk(&disk_key, location);
      btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
      btrfs_set_dir_type(leaf, dir_item, type);
      btrfs_set_dir_data_len(leaf, dir_item, 0);
      btrfs_set_dir_name_len(leaf, dir_item, name_len);
      name_ptr = (unsigned long)(dir_item + 1);
      write_extent_buffer(leaf, name, name_ptr, name_len);
      btrfs_mark_buffer_dirty(leaf);
out:
      btrfs_free_path(path);
      if (ret)
            return ret;
      if (ret2)
            return ret2;
      return 0;
}

struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
                                   struct btrfs_root *root,
                                   struct btrfs_path *path, u64 dir,
                                   const char *name, int name_len,
                                   int mod)
{
      int ret;
      struct btrfs_key key;
      int ins_len = mod < 0 ? -1 : 0;
      int cow = mod != 0;
      struct btrfs_key found_key;
      struct extent_buffer *leaf;

      key.objectid = dir;
      btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);

      key.offset = btrfs_name_hash(name, name_len);

      ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
      if (ret < 0)
            return ERR_PTR(ret);
      if (ret > 0) {
            if (path->slots[0] == 0)
                  return NULL;
            path->slots[0]--;
      }

      leaf = path->nodes[0];
      btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);

      if (found_key.objectid != dir ||
          btrfs_key_type(&found_key) != BTRFS_DIR_ITEM_KEY ||
          found_key.offset != key.offset)
            return NULL;

      return btrfs_match_dir_item_name(root, path, name, name_len);
}

struct btrfs_dir_item *
btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root,
                      struct btrfs_path *path, u64 dir,
                      u64 objectid, const char *name, int name_len,
                      int mod)
{
      int ret;
      struct btrfs_key key;
      int ins_len = mod < 0 ? -1 : 0;
      int cow = mod != 0;

      key.objectid = dir;
      btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
      key.offset = objectid;

      ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
      if (ret < 0)
            return ERR_PTR(ret);
      if (ret > 0)
            return ERR_PTR(-ENOENT);
      return btrfs_match_dir_item_name(root, path, name, name_len);
}

struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
                                struct btrfs_root *root,
                                struct btrfs_path *path, u64 dir,
                                const char *name, u16 name_len,
                                int mod)
{
      int ret;
      struct btrfs_key key;
      int ins_len = mod < 0 ? -1 : 0;
      int cow = mod != 0;
      struct btrfs_key found_key;
      struct extent_buffer *leaf;

      key.objectid = dir;
      btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
      key.offset = btrfs_name_hash(name, name_len);
      ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
      if (ret < 0)
            return ERR_PTR(ret);
      if (ret > 0) {
            if (path->slots[0] == 0)
                  return NULL;
            path->slots[0]--;
      }

      leaf = path->nodes[0];
      btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);

      if (found_key.objectid != dir ||
          btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY ||
          found_key.offset != key.offset)
            return NULL;

      return btrfs_match_dir_item_name(root, path, name, name_len);
}

struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
                        struct btrfs_path *path,
                        const char *name, int name_len)
{
      struct btrfs_dir_item *dir_item;
      unsigned long name_ptr;
      u32 total_len;
      u32 cur = 0;
      u32 this_len;
      struct extent_buffer *leaf;

      leaf = path->nodes[0];
      dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
      total_len = btrfs_item_size_nr(leaf, path->slots[0]);
      while(cur < total_len) {
            this_len = sizeof(*dir_item) +
                  btrfs_dir_name_len(leaf, dir_item) +
                  btrfs_dir_data_len(leaf, dir_item);
            name_ptr = (unsigned long)(dir_item + 1);

            if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
                memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
                  return dir_item;

            cur += this_len;
            dir_item = (struct btrfs_dir_item *)((char *)dir_item +
                                         this_len);
      }
      return NULL;
}

int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root,
                        struct btrfs_path *path,
                        struct btrfs_dir_item *di)
{

      struct extent_buffer *leaf;
      u32 sub_item_len;
      u32 item_len;
      int ret = 0;

      leaf = path->nodes[0];
      sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
            btrfs_dir_data_len(leaf, di);
      item_len = btrfs_item_size_nr(leaf, path->slots[0]);
      if (sub_item_len == item_len) {
            ret = btrfs_del_item(trans, root, path);
      } else {
            /* MARKER */
            unsigned long ptr = (unsigned long)di;
            unsigned long start;

            start = btrfs_item_ptr_offset(leaf, path->slots[0]);
            memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
                  item_len - (ptr + sub_item_len - start));
            ret = btrfs_truncate_item(trans, root, path,
                                item_len - sub_item_len, 1);
      }
      return 0;
}

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